CN1693915A

CN1693915A - Device for testing thermal relaxation time of semiconductor laser and testing method thereof

Info

Publication number: CN1693915A
Application number: CN 200510026554
Authority: CN
Inventors: 陈晨; 辛国锋; 方祖捷
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2005-06-08
Filing date: 2005-06-08
Publication date: 2005-11-09
Anticipated expiration: 2025-06-08
Also published as: CN100383541C

Abstract

The invention discloses a device for measuring the thermal relaxiation time of semi-conductor laser and the test method. The device includes a pulse power supply whose exportation end is linked with the semi-conductor laser, a collimation system and a spectrum instrument that on the laser, and a photoelectricity reduplicating tube at the slot of the spectrum instrument. The tube exportation end is linked with the Boxcar integral machine input end, the pulse power supply synchronous output end is combined with the Boxcar integral machine's trigger input end through the postponing electric circuit, and the computer's data collecting card at its input end is connected to the Boxcar integral machine's output end. The advantages are: It can work without detecting the various relations between the current of the laser and the slope efficiency when the temperature changes; The construction cost is low and the method is simple and steady.

Description

The proving installation of semiconductor laser thermal relaxation time and measuring method thereof

Technical field

The present invention relates to semiconductor laser, particularly a kind of proving installation of thermal relaxation time of semiconductor laser and method of testing thereof.

Background technology

The thermal characteristics of semiconductor laser is major issue in the practical application.High thermal resistance can cause the high temperature rise of laser instrument active area, thereby causes that laser threshold current becomes big, slope efficiency descends, output power reduces, and more seriously influences the life-span of device.Except thermal resistance, another thermal characteristics parameter of semiconductor laser is a thermal relaxation time.For the semiconductor laser under the pulsed operation state, the thermal relaxation time parameter is a very important parameters.

When semiconductor laser applied square wave current, the laser instrument junction temperature rose in pulse gradually, and through after a while, junction temperature reaches steady-state value.Variations injunction temperature can be expressed as:

T＝T ₀+R _thP[1-exp(-Δt/τ)] (1)

R wherein _ThBe the laser heat resistance, P is for injecting hot-fluid, and τ is a thermal relaxation time, T ₀Laser instrument junction temperature when not having electric current to inject.

Thermal relaxation time has reflected the speed that the laser instrument junction temperature raises.For the laser instrument of a few thing at short pulse, then the temperature rise in pulse is very little if its thermal relaxation time is big; If the little then laser instrument of thermal relaxation time junction temperature just reaches steady-state value in a short period of time.

The existing testing scheme of thermal relaxation time is:

Technology [1] (H.I.Abdelkader formerly, H.HHausien, and J.D.Martin.Temperature rise and thermal rise-time measurement of a semiconductorlaser diode.Rev.Sci.Instrum.63 (3), March 1992:2004-2007) in, H.I.Abdelkader has studied the threshold current of semiconductor laser and the slope efficiency variation relation with junction temperature, by different pulses laser optical variable power constantly under the test pulse work, obtain different junction temperature liters constantly, thereby calculate the thermal relaxation time value.But the laser optical performance number is smaller under the short pulse, and different laser optical variable power constantly are difficult to accurate mensuration, need relatively more accurate equipment.Technology [2] (M.Voss formerly, C.Lier, U.Menzel, A.Barwolff, andT.Elsaesser.Time-resolved emission studies of GaAs/AlGaAs laser diodearrays on different heat sinks.J.Appl.phys.79 (2) .15 January 1996:1170-1172) in, M.Voss et.al. tests the spectrum of different switching times then and obtains the dynamic thermal characteristics of laser instrument by spectrometer receiving trap CCD is provided with photoswitch.This technology paired pulses light signal adopts photoswitch, requires the accurate gauge tap time, and control requires too high to light signal.

Summary of the invention

The present invention overcomes above-mentioned the deficiencies in the prior art, and a kind of measurement mechanism and method of testing thereof of thermal relaxation time of semiconductor laser is provided,

Technical solution of the present invention is as follows:

A kind of measurement mechanism of thermal relaxation time of semiconductor laser, the formation of this device is: a pulse power, the output termination semiconductor laser of this pulse power, laser working direction along this semiconductor laser is colimated light system and spectrometer successively, photomultiplier is positioned at the output slit of described spectrometer, the input end of the output termination Boxcar integrator of photomultiplier, the synchronous output end of the described pulse power is through the triggering input end of delay circuit connection Boxcar integrator, and computing machine input end data collecting card connects the Boxcar integrator output terminal.

The method of testing of the thermal relaxation time of semiconductor laser of the present invention is characterized in that this method comprises the following steps:

1. at first set the parameter of Boxcar integrator: sample-pulse signal T _gBe 0.5us, sweep time T _sBe 150s; Next delay time of setting delay circuit is no more than 5ms; The slit width of spectrometer is 10 μ m-40 μ m;

2. open the laser pulse power supply, fixed light spectrometer scanning wavelength λ _S1, the sample-pulse signal scanning photomultiplier that the Boxcar integrator produces is by the optical power signals signals converted, and computing machine is exported the Boxcar integrator and is gathered, and obtains electrical signal data I ₁L _i, from the series of electrical signals data I _iAnd corresponding time t obtains the time t=u that electrical signal peak occurs _M1

3. change the scanning wavelength λ of spectrometer _Si(i=2 3....15), repeats the second step process, obtains series of electrical signals peak value time of occurrence u _Mi(i=2,3....15).

4. with scanning wavelength λ _SiWith peak value time of occurrence u _MiUtilize following formula to obtain τ _i, on average obtain the thermal relaxation time value of consult volume τ of this laser instrument again:

τ = - \frac{u_{m}}{\ln [1 - \frac{λ_{S} - λ_{P} (T_{0})}{λ_{T}^{'} R_{th} P}]}

In the formula: λ _sBe the fixing scanning wavelength value of spectrometer, u _mBe corresponding luminous power peak value time of occurrence, λ _p(T ₀) be the initial spike wavelength, λ _T' be the spectroscopic temperature coefficient.

The delay time of described delay circuit should be 0.2ms.

Described slit width is 30 μ m.

Compare with other method of testing, advantage of the present invention is: do not need testing laser device threshold current and the slope efficiency variation relation with junction temperature; Use electric switch, control easily than photoswitch, the whole experiment device cost is low, builds easily, and method is simple, good stability.

Description of drawings

Fig. 1 is the structural representation of apparatus of the present invention.

Fig. 2 is the scanning wavelength that obtained by test result and the graph of a relation of luminous power time to peak.

Among Fig. 1: 1-semiconductor laser, the 2-pulse power, 3-delay circuit, 4-colimated light system, 5-spectrometer, 6-photomultiplier, 7-Boxcar integrator, 8-computing machine

Embodiment

The invention will be further described below in conjunction with embodiment.

See also shown in Figure 1 earlier.Fig. 1 is the structural representation of apparatus of the present invention embodiment.As seen from the figure, the proving installation of the thermal relaxation time of semiconductor laser of the present invention, the formation that it is characterized in that this device is: a pulse power 2, the output termination semiconductor laser 1 of this pulse power 2, laser working direction along this semiconductor laser 1 is colimated light system 4 and spectrometer 5 successively, photomultiplier 6 is positioned at the output slit of described spectrometer 5, the input end of the output termination Boxcar integrator 7 of photomultiplier 6, the synchronous output end of the described pulse power 2 is through the triggering input end of delay circuit 3 connection Boxcar integrators 7, and computing machine 8 input end data collecting cards connect Boxcar integrator 7 output terminals.

Utilize the described device of Fig. 1 to carry out the method for testing of the thermal relaxation time of semiconductor laser, comprise the following steps:

1. at first set the parameter of Boxcar integrator 7: sample-pulse signal T _gBe 0.5us, sweep time T _sBe 150s; Next delay time of setting delay circuit 3 is 0.2ms.The slit width of spectrometer 5 is that 1 described slit width is 30 μ m;

2. open laser pulse power supply 2, fixed light spectrometer 5 scanning wavelength λ _S1, the sample-pulse signal scanning photomultiplier 6 that Boxcar integrator 7 produces is by the optical power signals signals converted, and 7 outputs of 8 pairs of Boxcar integrators of computing machine are gathered, and obtain electrical signal data I ₁L _i, from the series of electrical signals data I _iAnd corresponding time t obtains the time t=u that electrical signal peak occurs _M1

3. change the scanning wavelength λ of spectrometer 5 _Si(i=2 3....15), repeats the second step process, obtains series of electrical signals peak value time of occurrence u _Mi(i=2,3....15).

τ = - \frac{u_{m}}{\ln [1 - \frac{λ_{s} - λ_{P} (T_{0})}{λ_{T}^{'} R_{th} P}]}

The optical power signals time to peak the needed time occurs for beginning to be injected into the laser optical power peak from current impulse.When Boxcar integrator 7 output datas are gathered, need to gather sample-pulse signal simultaneously.Set when collecting sample-pulse signal in the experiment, begin to gather Boxcar integrator 7 output signals.Thereby each Boxcar integrator 7 output signal collections all are to begin at synchronization.In the experimentation, because sampling pulse width is 0.5 μ s, the data collecting card acquisition rate is up to 40k/s, is difficult for sampling.Therefore be the synchronizing signal of width 250 μ s with the sample-pulse signal broadening, send into computing machine 8 samplings.When collecting this signal rising edge, data collecting card begins to gather Boxcar integrator 7 output signals.

Fig. 2 is fixed wave length λ _sWith average peak time u _mGraph of a relation.By (3) formula, when

\frac{λ_{s} - λ_{P} (T_{0})}{λ_{T}^{'} R_{th} P} < < 1

The time, u _mWith λ _sLinear change, (3) formula is written as:

τ = - \frac{u_{m}}{\frac{λ_{s} - λ_{P} (T_{0})}{λ_{T}^{'} R_{th} P}} .

So can calculate this laser heat relaxation time values by the slope of matched curve among the figure (2) is 390 μ s.

Claims

The proving installation of the thermal relaxation time of 1 one kinds of semiconductor lasers, the formation that it is characterized in that this device is: a pulse power (2), the output termination semiconductor laser (1) of this pulse power (2), laser working direction along this semiconductor laser (1) is colimated light system (4) and spectrometer (5) successively, photomultiplier (6) is positioned at the output slit of described spectrometer (5), the input end of the output termination Boxcar integrator (7) of photomultiplier (6), the synchronous output end of the described pulse power (2) is through the triggering input end of delay circuit (3) connection Boxcar integrator (7), and computing machine (8) input end data collecting card connects Boxcar integrator (7) output terminal.
2, utilize the described device of claim 1 to carry out the method for testing of the thermal relaxation time of semiconductor laser, it is characterized in that this method comprises the following steps:

1. at first set the parameter of Boxcar integrator (7): sample-pulse signal T _gBe 0.5us, sweep time T _sBe 150s; Next delay time of setting delay circuit (3) is no more than 5ms; The slit width of spectrometer (5) is 10 μ m-40 μ m;

2. open laser pulse power supply (2), fixed light spectrometer (5) scanning wavelength λ _S1, the sample-pulse signal scanning photomultiplier (6) that Boxcar integrator (7) produces is by the optical power signals signals converted, and computing machine (8) is exported Boxcar integrator (7) and is gathered, and obtains electrical signal data I ₁... l _i..., from the series of electrical signals data I _iAnd corresponding time t obtains the time t=u that electrical signal peak occurs _M1

3. change the scanning wavelength λ of spectrometer (5) _Si(i=2 3....15), repeats the second step process, obtains series of electrical signals peak value time of occurrence u _Mi(i=2,3....15).

4. with scanning wavelength λ _SiWith peak value time of occurrence u _MiUtilize following formula to obtain τ _i, on average obtain the thermal relaxation time value of consult volume τ of this laser instrument again:

$τ = - \frac{u_{m}}{\ln [1 - \frac{λ_{s} - λ_{P} (T_{0})}{λ_{T}^{'} R_{th} P}]}$

In the formula: λ _sBe the fixing scanning wavelength value of spectrometer, u _mBe corresponding luminous power peak value time of occurrence, λ _p(T ₀) be the initial spike wavelength, λ _T' be the spectroscopic temperature coefficient.
3, the method for testing of the thermal relaxation time of semiconductor laser according to claim 2 is characterized in that the delay time of described delay circuit (3) should be 0.2ms.
4, the method for testing of the thermal relaxation time of semiconductor laser according to claim 2 is characterized in that described slit width is 30 μ m.